This is a true story about the use of WD-40. Folks who are using it to clean pots and switches are invited to take it for what it is worth.
At one time I worked for Bell Labs. Back a good many years there was a hurricane in Florida which drowned the telephone exchange at the Homestead Air Force Base. Bell System folks from all over the country converged to help dry out and restore the exchange, an electromechanical "crossbar" type. My Laboratory was responsible for "Electromechanical Switching Equipment" including the relays and crossbar switches in the exchange, so we had an engineer there with the crew. The folks decided to spray the crossbar switches with WD-40. It did indeed displace the water and restore the switches to operating condition, as the "WD" implies. But several months later as the more volatile components of the WD-40 evaporated and the less volatile components remained behind, the switch mechanisms started to gum up and the switch contacts went high resistance to open circuit. Finally the entire exchange had to be scrapped out and replaced.
Because of this experience, I do not use WD-40 to "clean" any switch contacts or potentiometers in my radio equipment.
Jim Hanlon, W8KGI